1. Field of the Invention
This invention relates to a floating magnetic head of the composite type wherein a slider and a magnetic core are joined integrally together.
2. Description of the Prior Art
FIG. 4 shows an example of floating magnetic heads of the composite type. An end portion of a slider 11 is formed with a joint groove 12 for receiving a magnetic core 13, in this joint groove 12 being assembled the magnetic core 13. This magnetic core 13 is composed of a pair of half cores 14 and 15, their abutting surfaces defining a magnetic gap 16. FIG. 5 is a front view of the aforementioned magnetic core section. Each of the half cores 14 and 15 is made of an oxide magnetic substance such as Mn-Zn ferrite, these half cores being joined together via a joint material such as glass. A joint portion thus formed defines the magnetic gap 16. In the thus configured magnetic core 13, hitherto, a gap depth d is one of the important factors, and by controlling the gap depth there can be obtained a desired magnetic characteristic. The reason is that if the gap depth d is too large the magnetic flux cannot fly toward the side of a magnetic recording medium, whereas if the gap depth is too small there occurs magnetic saturation and a desired magnetic characteristic cannot be obtained.
In conventional floating magnetic heads of the aforementioned type, the control of the gap depth d is achieved, after the magnetic core 13 is joined with the slider 11, by lapping one side facing opposite the magnetic recording medium and stopping lapping when an appropriate lapping amount has been attained. Thus, the gap depth d cannot visually be confirmed. Accordingly, the control of the gap depth d must rely on experience, perception and the like, and occurrence of variations in preciseness cannot be avoided.
On the other hand, in the field of 8 mm video and the like, in order to enhance the recording density, a metallic magnetic thin film made, for example, of Permalloy or Sendust is generally attached inside the magnetic gap formed by the pair of half cores 14 and 15. This configuration is referred to as a so-called metal-in-gap type which is characterized in that because the saturation magnetic flux density of a metallic substance is high, magnetic saturation can hardly occur and recording of high density can be achieved. It will be thought to apply a magnetic core of the aforementioned type to the floating magnetic head, but, the difficulty in control of the gap depth d also exists in this metal-in-gap type.